Centerless finishing machine



July 5, 1966 J. M. FOWLE 3,258,804

CENTERLESS FINISHING MACHINE Filed June 1, 1965 INVENTOR. JOHN M. FOWLEQ 3,, b m-2A A 7' TO/QNE V United States Patent 3,258,804 CENTERLESSFINISHING MACHINE John M. Fowle, Los Altos Hills, Calif, assignor toDura- Bond Bearing Company, Palo Alto, Calif., 21 corporation ofCalifornia Filed June 1, 1965, Ser. No. 460,221 4 Claims. (Cl. -88) Thisinvention rel-ates generally to the centerless finishing art wherein awork piece having a generally cylindrical form is finished while thework piece is supported at its periphery and not on centers. Morespecifically the invention is directed to the problem of removing b-urrsand sharp edges from machined parts. An example of such a part is abearing sleeve having surface holes, slots or other machined cavities.

The main object of the present invention is the provision of acenterless finishing machine which is particularly adapted to removeburrs and sharp edges from cylindrical work pieces in one pass throughthe machine. In this connection there are presently avail-ablecenterless deburring machines employing wire brushes in which theconventional centerless grinding principle is employed except that arotating brush is substituted for the large rotating grinding wheelemployed in the typical centerless grinding operation. An importantdisadvantage of conventional centerless deburring devices is that twopasses are required through the machine to satisfactorily complete thedeburrin-g operation, or two machines are required through which thework piece is passed successively. The reason for the two separateoperations is that the rotating wire brush is effective to clean onlythat edge of a hole or cavity which the wires of the brush strike last.In other words, the edge of a hole or cavity closest to the approachingwires of the brush do not receive the same impact as the edges lastengaged by the wires of the brush. The reason for this is that the wiresof the brush enter the hole or cavity and are impacted against the edgesthey engage as they leave the cavity. For example a bearing sleevehaving a drilled hole will not be satisfactorily deburred along the edgeof the hole which the wires of the brush engage first but will besatisfactorily deburred along the edge which they engage last. Thiseffect is seen in FIG. 4 of the drawings. In view of this particulareffect it has been customary in the past to pass the work piece througha center-less deburring machine with one end of the piece leading andthen pass it through again with the opposite end leading. This procedureresults in reversal of the edges that are exposed to the greatestabrasive action of the wire of the brushes thereby achievingsatisfactory deburring and finishing effect.

By the present invention it is only necessary to pass the work piecethrough the machine once to achieve the desirable effect of having thewires of the brush imp-act the entire circumferential extent of theouter edge of the hole, slot or cavity formed in the periphery of thework piece.

Other objects and advantages of the invention will be apparent from thefollowing specification and from the drawings.

FIG. 1 is a top plan view of the essential portions of the centerlessfinishing machine. Safety guards and other elements normally associatedwith this type of equipment are omitted from the drawings for clarity.

FIG. 2 is a front elevation of the machine of FIG. 1 as taken in a planeindicated by lines 2-2 of FIG. 1.

FIG. 3 is an enlarged cross section taken in a plane indicated by lines3-3 of FIG. 1.

FIG. 4 is a schematic fragmentary view showing the cooperation betweenbrush and the work piece.

The invention makes use of the well known centerless machining principleand includes a regulating wheel of abrasive material designated I. Saidwheel is shown on the drawings as supported by a bearing 2 at one endand driven at its opposite end from a motor 3. As is well known the axisof regulating wheel 1 is inclined slightly to the path of travel of thework pieces so that the periphery of said wheel supports the work piecesand at the same time feeds the same in a direction generally axially ofthe wheel.

In this description the work pieces illustrated are sleeve bearings 7which are fed to the machine along an inclined chute 8 and which thenpass along the regulating wheel 1 supported on a lower work rest blade 9(FIG. 3). Said work rest blade 9 extends the length of regulating wheel1 and is supported at one end on a blade support structure 10 and at itsopposite end in a similar blade support structure 11. This structure isconventional and no claim is made thereto except in combination with thepresent invention. By the present invention it is necessary to providean upper work res-t blade 12 which is also mounted in the blade supportstructure as best seen in FIG. 3. It will be noted that the work restblades 9 and 12 are spaced apart a distance slightly greater than theextent of the work piece 7 at said blades so that said pieces may engagethe blades successively.

The work pieces 7 from supply chute 8 are first engaged by a wire brush15 which is indicated in FIG. 1 as rotating in a direction to urge thework pieces into engagement with the lower work rest blade 9. It will beunderstood that the regulating wheel 1 rotates at a relatively low rateof speed while the wire brush 15 rotates at a relatively high rate ofspeed.

Wire brush 15 is fixed to one end of a shaft 16 which is supported in abearing 17 and which is provided at its opposite end with a pulley 18driven through a belt 19 from a motor 20.

Alongside brush 15 and substantially coaxial therewith is a second wirebrush 21 fixed to one end of a shaft 22 supported in a bearing 23. Asimilar drive including motor 24 and belt 25 is employed to rotate brush21 in a direction opposite to the direction of brush 15.

After the work pieces 7 leave the region of the first brush 15, theycontinue through the machine until they are subjected to the thrust ofthe second brush 21. The thrust of this brush is, of course, in theopposite direction or upward. This lifts the work piece 7 upward intoengagement with the upper work rest blade 12. The face angle of theupper blade is disposed opposite to the lower blade so that the oppositeangle combined with the opposite direction of force result in acontinuation of the positive driving action of the regulating wheel 1.

After the work pieces 7 have been discharged from the work rest blades 9and 12 they are conveyed away on a discharge chute generally designated27.

By the above described structure it will be apparent that any aperturesformed in the work pieces 7 will be smoothed and deburred completely inone pass through the machine since the upper and lower edges of suchapertures or cavities will both be exposed to the impact action of thewires of the brushes. As best seen in FIG. 4 the brush 15 has the effectof smoothing out the lower edge 31 of aperture 29 in work piece 7 whileleaving the upper edge 30 sharp. However the subsequent engagement ofwork piece 7 with the oppositely rotating brush 21 completes thedeburring operation by smoothing out upper edge 30. The side edges ofsuch holes or apertures will, of course, also be subject to thesmoothing action of the wires of the brushes.

It will be apparent from FIG. 3 that the work rest blades 9 and 12should be spaced apart a distance such that only a slight amount ofclearance exists between one blade and the work piece when the workpiece is being urged against the opposite blade by whatever one of thetwo brushes it engages.

In many centerless operations the work pieces are disposed in an abovecenter position which often has certain advantages in operations ofgreat accuracy. In a wire brush deburring operation of the type forwhich the present invention is particularly suited above centeroperation holds no advantage over on center operation. In the abovedescribed structure it has been assumed that the work pieces aresubstantially on center with respect to the common axis of brushes 15,21.

It Will be understood by analogy to conventional centerless grindingoperations that the speed of rotation of the regulating wheel 1 isrelatively low and may impart a peripheral speed to the work piecesbetween 50 and 250 feet per minute. The peripheral speed of the brushesshould be in the order of from 4000 to 7000 feet per minute. Insofar asthe relative speed between a brush and the Work is concerned it will benoted that in one case the speeds are additive while in the other theeffective speed is the diiference between the two surface speeds. In adeburring operation it will be appreciated that these dilferences inworking speeds between the two stages is inconsequential and do not haveany practical effect on the deburring operation.

As noted above, the usual auxiliary components associated with this typeof equipment have been omitted from the description including the usualdressing wheel for maintaining the regulating wheel in good condition.Also the means for feeding the regulating wheel 1 toward the work hasbeen omitted for clarity.

It should also be noted that the present invention contemplatespolishing and grinding operations as well as deburring operations inorder to obtain whatever advantages accrue from the dual finishingoperations to which the invention lends itself.

The above veryspecific description of the preferred form of theinvention should not be taken as restrictive as it will be apparent thatvarious modifications in design may be resorted to without departingfrom the scope of the following claims.

I claim:

1. Centerless finishing apparatus comprising:

means providing centerless support for a work piece,

a regulating wheel including drive means for feeding said piece along apath of travel in one direction,

a first finishing member on the opposite side of said path from saidregulating wheel and adapted to engage said piece,

means driving said member in one direction,

a second finishing member alongside said first member and in engagementwith said piece,

means driving said second finishing member in a direction opposite tosaid first member.

2. A device according to claim 1 wherein'said centerless supportincludes a pair of vertically spaced work rest blades for supportingsaid piece against substantial vertical movement.

3. A device according to claim 1 wherein said finishing members are wirebrushes.

4. Apparatus for deburring generally cylindrical work pieces comprising:

means providing centerless support for a Work piece,

a rotating regulating wheel for feeding said piece along a path oftravel in one direction,

a first brush on the opposite side of said path from said regulatingwheel and in deburring engagement with said work piece,

means driving said brush in one direction,

a second brush substantially coaxial with said first brush and indeburring engagement with said Work piece,

means driving said second brush in a direction opposite to said firstbrush.

References Cited by the Examiner UNITED STATES PATENTS 1,692,985 11/1928Gallison 1588 X 2,238,720 4/1941 Duaei et al 1588 3,218,658 11/1965Collins et al. 15-88 CHARLES A. WILLMUTH, Primary Examiner.

1. CENTERLESS FINISHING APPARATUS COMPRISING: MEANS PROVIDING CENTERLESSSUPPORT FOR A WORK PIECE, A REGULATING WHEEL INCLUDING DRIVE MEANS FORFEEDING AND PIECE ALONG A PATH OF TRAVEL IN ONE DIRECTION, A FIRSATFINISHING MEMBER ON THE OPPOSITE SIDE OF SAID PATH FROM SAID REGULATINGWHEEL AND ADAPTED TO ENGAGE SAID PIECE, MEANS DRIVING SAID MEMBER IN ONEDIRECTION, A SECOND FINISHING MEMBER ALONGSIDE SAID FIRST MEMBER AND INENGAGMENT WITH SAID PIECE, MEANS DRIVING SAID SECOND FINISHING MEMBER INA DIRECTION OPPOSITE TO SAID FIRST MEMBER.